The present continuation proposal aims to study developmental brain-behavior relationships through further longitudinal assessment of the language, cognitive, academic and emotional sequelae presented by children with unilateral left or right brain lesions. Thirty-eight children with CT scan confirmed unilateral lesions of vascular origin (24 left and 14 right) have been studied thus far in comparison to control children matched by age, sex, race, social class; a total of 50 lesioned and 50 control children are projected for inclusion during the next 3 years. Continued study will permit: 1) more detailed longitudinal follow-up of the behaviors examined to date including syntactic comprehension and production, conceptual aspects of semantics, phonological abilities as revealed in speech, reading and spelling, IQ and cognitive pattern stability over time, and reading, math and written language achievement; 2) expanded study of behaviors previously not examined addressing personality and emotional adjustment and aspects of cognitive processing, including impulse inhibition, ability to sustain and shift attention, visual and auditory memory, and visual-perceptual abilities; and 3) more refined definition of the neuroanatomic characteristics of the unilateral brain lesions and volumetric quantification of lesion size through three dimensional reconstructions of magnetic resonance images. Thus, more reliable relationships may be drawn between behavioral measures and lesion site and size. Theoretically, the study will continue to address the issues of early hemispheric specialization for cognitive functions versus the ability of higher cortical functions to recover following unilateral lesions incurred in childhood. The clinical significance of the study is in detailing the nature of an prognosis for behavioral sequelae following brain lesions in children, a concern basic to the clinical practice of professionals caring for brain lesioned children and of fundamental importance to these children and their families.